Mold for concrete shingles.



CUlitT 1t. BIPRJKEMRDT, 0F TEANECK, NEW JERSEY, ASSIGNOR 0F GIVE-HMI? T0 TURN d.. SCHWATH, 0F ELIZABETH, NEW JRSEY.

norm ron, concnn'rn smnenns.

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' To all whom it mayenne-ern.'

Be it known that l., @UBT R. BURKHRDT, s citizen of the lllnited `States of America, end e resident oti'leeneck, county of Bec gen, and State of New Jersey, have invented certain new and useful improvements in olds for Concrete Shingles, of which the following is s. specification, reference being lisd to the accompanying drawings, forming n part thereof.

My intention relates to the srt of menufactnring concrete shingles and has special reference to molds adapted to be utilized in hydraulic or other presses i'or this purpose.

Une object of my invention is to provide n simple mold structure that shell be reliable in operation und which shell embody means for avoiding distortion of the press heeds or strains tending to distort them, due to the tapered forni of the shingle, when the press is operated. l

ln order that my invention may be thoroughly understood, I will'non'7 proceed` to describe the seme in the following specifics tion, und will then point out the novel feetnrcs thereof in appended claims.

Referring to the drawings:

Figure 1 is u transverse sectional elevation taken on the line 1--1 of Fig. 3, and

Fig. 2 is s sectional elevation et right angles to Fig. l, and taken on the line 2-2 of Fig. 3.

Fig. 3 is a. plan View of a mold which con stitutes en embodiment of my invention. K

Figs. 4 `and 5 are perspective views of an asbestos cement shingle such es the mold oi the previous gures is 'adapted to produce.

Referring to Figs. 1, 2 and 3 the structure here shown comprises a mold frame 10 lieving-a. lienge or edge strip 11, e removable block 12 which is tted loosely into the mold freine and has its bottom edges chamfered et 13 to receive the flange or edge strip of the freine.

The I1clock 12 is further provided with re.-4

cesses 14 in which springs 15 are disposed. Mounted on the block and restino* on the springs 15 near one endis c. mold plnte'l.

As shown 1n Fig. 2, the mold'is prefernbly l divided into two ports by e partition Jwhich is enlarged et the bottom to form ledges 18 corres ending to the Hsnges 1 1 on the sides. ln t e seme wey the block 12 is Specification of Letters Patent.

either be arranged for one block and adapted Application filed September 1, 15117. Serial No. 139,404.

to produce d single article at one operations' or it may loe-subdivided into s. plurality oli sections by one or more partitions, and by utilizing blocks corresponding' vto the number of spaces.

Each mold block section hes its upper edges cut back to form a space into which en apron or flange 19 of the mold plete extends. The arrangement of parts is such that the fia'nge at all times overhnngs the edges oli the mold block on which it is mounted, thereby preventing e plastic materiel from Working its Way under the mold pleteend between the plete and the block.

`20 designates o. stationery ress heed and Z1 s movablepress heed. T 1e press is not shown and may be formed in any suitable manner and may for exemple be constructed as described in my copending epplicntion ISerial No 101,461 tiled .lune 3, 1916.

The springs are relatively sti und ere Vfully expanded except at the fined movement of the-press when' they yield to permit the press head to move slightly farther end tette up for the shrinkage of the thick part of the shingle after the thin part of the shingle is entirely solid and practically non-com pressible. y v

The inld plate is so formed `that when the springs 5 lare compressed end it restt in. the bloclt the specs then eiiisting be the mold plete end the stationery mein n ot the press, is such as to produce the desired shingle form. This es shown in Figs. tend 5, is preferably tapered from end to end, hss edge i'iotches 23, end cored `recesses 211 to reduce the Weight in the thicker part of the shingle. y

If a tapered mold. plate is utilized Without any springs as if, for exemple, the springs 15 were removed, and the mold iilled end the press actuated, the strains dueto the reaction of the press, are not parallel to the direction of the press movement or, in other Nvords, they ere' out of slinement with the press action and tend to produce strains in lllo ico i and while I trated has been demonstrated in praetice do not wish to be limited to any theory of operation, I now believe that, the operation is correctly outlined as follows:- p

Assuminfz,r first that the opposed press head surfaces are parallel and normal tothe aetion of the press, the'inold plate whieh determines the form of the shingle il 4solidl \Y mounted on the base of the mold, provides a tapered mold space which is filled with a soft mixture of rement and asbestos `fibcrs.

This softmass 'contains a great deal of water, the thicker part eontaining (,:onsequent l v more than the thinner part.

The press head against .which the. plastic tively high temperature in any suitable manner. Consequenthv1 when high pressure. is exerted the water is iirst evaporated trom the thinner part of the shingle and the shrinkage in this part' is less than th'e shrinkage in the thick part. (`onsequent lv the thin part .sets and becomes a praetieallv noneompressible solid mass preventing t'urther motion `of the press head. where-is the thicker part requires a very slightly farther motion of the members in order to take up the additional shrinkage in this part of the shingle.

It is this difference in the distributit-)n of Water and the difference in shrinkage which is believed to put a strain on the press` and the springs of my present invention are provided in sueh a way as to overcome the Strains on the press by permittinga very slight compression of the sprin`r under the thin end to allow the necessary vadditional movement. of the press to take up the shrinkage in thethick part, of the shingle.

l. 'A press mold Comprising a mold. frame adapted to tit against one of the heads of the press and having a movable block, a mold plateI mounted on the block, and a spring between the mold plate and the bloek, otl'set from the center..

.2. A press mold romprising a mold frame I, adapted to tit. against one of the heads oll mass lssqueezed is maintainedat a relathe press and havingr a movable bleek, a mold plate mounted on the bloek and hav in;r a flange overlmnging the edges thereof, and a spring for resiliently supporting one end otl the, mold plate.

3. A press mold comprising a parallel surface, a block adapted to he engaged by one of the press heads. a mold plate. ot tapered form mounted on the block and resilient means for elevating the thick end of the mold plate.

4. A press mold eomprising,r a parallel surface. a blot-k adapted to be engaged by one of the press heads, a mold plate of tapered form mounted on thefbloek. and a spring for elevating the. thiek end of the mold vplate to permit a slight additional movement ofthe press head after the thin.

part ot' the article being molded is set.

In .witness whereotl I have hereunto set. tn v hand this 27th davot August, 1917.

` CURT R. BURKHARDT.y 

